Kick detection system and method for drilling well and associated well drilling system

ABSTRACT

A kick detection system for drilling a well including an ultrasonic module for transmitting signals to a returning drilling fluid from the well, and receiving corresponding backscatter signals; and a process apparatus for obtaining a flow characteristic of the returning drilling fluid based on the backscatter signals, and detecting a kick based on the flow characteristic of the returning drilling fluid and drilling related data. A well drilling system including a drilling string for guiding a drilling bit and a drilling fluid to a well; a conduit defining a channel for accommodating the drilling string and a returning drilling fluid from the well; and the kick detection system. A kick detection method is also described.

BACKGROUND OF THE INVENTION

Embodiments of the invention relate generally to a kick detection system and method for drilling a well and an associated well drilling system.

The exploration and production of hydrocarbons from subsurface formations have been done for decades. Due to the limited productivity of aging land-based production wells, there is a growing interest in the hydrocarbon recovery from subsea wells. Generally, for drilling an offshore well, a rotatable drill bit attached to a drill string is used to create the well below the seabed. The drill string allows control of the drill bit from a surface location, typically from an offshore platform or a drill ship. A riser is also deployed to connect the platform at the surface to the wellhead on the seabed. The drill string passes through the riser so as to guide the drill bit to the well.

During well drilling, the drill bit is rotated while the drill string conveys the necessary power from the surface platform. Meanwhile, a drilling fluid is circulated from the surface platform through the drill string to the drill bit, and is returned to the surface platform through a space between the drill string and a casing or a riser. The drilling fluid maintains a hydrostatic pressure to counter-balance the pressure of fluids coming from the well and cools the drill bit during operation. In addition, the drilling fluid mixes with materials excavated during the creation of the well bore and carries the materials to the surface for disposal.

Under certain circumstances, the pressure of fluids entering the well from the formation may be higher than the pressure of the drilling fluid. This may lead to an unwanted influx of fluid into the well, known in the industry as a “kick”. Under some circumstances, the occurrence of a kick brings potential for catastrophic equipment failures and the attendant potential harm to well operators and the environment.

Well operators are keenly aware of the destructive potential of such unwanted influxes and continuously monitor inflows and outflows of the drilling fluid at the sea surface in order to detect kick. However, it is difficult to employ a traditional device for monitoring the drilling fluid in the surface platform due to the volume and complexity of the traditional device. Moreover, there is a relative long time (e.g., tens of minutes) between a moment when a disturbance of the fluid occurs at the well and when the disturbance is detected at the sea surface, i.e., when a kick warning is obtained by the operators at the sea surface, the kick may have already happened.

Therefore, it would be desirable to provide new and improved kick detection systems and methods for drilling wells and associated well drilling systems.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, the present disclosure relates to a kick detection system for drilling a well, comprising an ultrasonic module for transmitting signals to a returning drilling fluid from the well, and receiving corresponding backscatter signals; and a process apparatus for obtaining a flow characteristic of the returning drilling fluid based on the backscatter signals, and detecting a kick based on the flow characteristic of the returning drilling fluid and drilling related data.

In another aspect, the present disclosure relates to a well drilling system comprising a drilling string for guiding a drilling bit and a drilling fluid to a well; a conduit defining a channel for accommodating the drilling string and a returning drilling fluid from the well; and a kick detection system according to embodiments of the present invention.

In yet another aspect, the present disclosure relates to a kick detection method for drilling a well, comprising transmitting signals to a returning drilling fluid from the well, and receiving corresponding backscatter signals; obtaining a flow characteristic of the returning drilling fluid based on the backscatter signals; and detecting a kick based on the flow characteristic of the returning drilling fluid and drilling related data.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the present disclosure will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic view of a well drilling system in operation in accordance with an embodiment;

FIG. 2 is a schematic view of a kick detection system in accordance with an embodiment;

FIG. 3 is a schematic view of ultrasonic sensors disposed on a conduit in accordance with an embodiment;

FIG. 4 is a schematic partial view of a conduit with an ultrasonic module disposed thereon in accordance with an embodiment;

FIG. 5 is a schematic flow diagram of a kick detection method for drilling a well in accordance with an embodiment; and

FIG. 6 is a schematic flow diagram of the step 23 of FIG. 5 in accordance with an embodiment.

DETAILED DESCRIPTION

In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in one or more specific embodiments. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of the present disclosure.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms “first,” “second,” and the like, as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Also, the terms “a” and “an” do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. The term “or” is meant to be inclusive and mean either any, several, or all of the listed items. The use of “including”, or “comprising” and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

FIG. 1 illustrates a schematic view of a well drilling system 10 in operation in accordance with an embodiment of the present invention. FIG. 2 illustrates a schematic view of a kick detection system 100 in accordance with an embodiment of the present invention. In some embodiments, the drilling system 10 is configured to drill a well for exploration and production of hydrocarbons, such as fossil fuels. Non-limiting examples of the wells include onshore and offshore wells. In some embodiments, the drilling system 10 is configured to drill the offshore well.

As illustrated in FIG. 1, the well drilling system 10 comprises a drilling string 14 for guiding a drilling bit 15 and a drilling fluid 101 to a well 104, a conduit 13 defining a channel 103 for accommodating the drilling string 14 and a returning drilling fluid 102 from the well 104, and a kick detection system 100.

The drilling string 14 comprises a drilling pipe (not shown) assembled to an offshore device 106, such as an offshore platform or a drill ship. The drilling bit 15 is assembled to an end of the drilling string 14. During a drilling operation, the drilling fluid 101 is guided to the well 104 through the drilling pipe and the drilling bit 15 rotates to perform the drilling below the seabed 105.

An end of the conduit 13 is assembled to the offshore device 106, and the other end of the conduit 13 is connected with a wellhead of the well 104.

During drilling, the drill string 14 guides the drilling bit 15 to the well 104 and rotates the drilling bit 15. The drilling fluid 101 is circulated from the offshore device 106 through the drilling string 14 to the drilling bit 15, and returns to the offshore device 106 as the returning drilling fluid 102 through the channel 103.

The drilling fluid 101 maintains a hydrostatic pressure to counter-balance the pressure of fluids in the formation and cools the drilling bit 15 while also carrying materials excavated, such as cuttings including crushed or cut rock during drilling the well 104, to the offshore device 106. In some embodiments, the drilling fluid 101 may comprise water, oil and various additives. The returning drilling fluid 102 may include a mixture of the drilling fluid 101 and the materials excavated during drilling the well 104. On the offshore device 106, the returning drilling fluid 102 may be treated to remove solids and then re-circulated for use as the drilling fluid 101.

The kick detection system 100 comprises an ultrasonic module 11 for transmitting signals to the returning drilling fluid 102 from the well 104 and receiving corresponding backscatter signals, and a process apparatus 12 for obtaining a flow characteristic of the returning drilling fluid 102 based on the backscatter signals and detecting a kick based on the flow characteristic of the returning drilling fluid 102 and drilling related data.

In some embodiments, the ultrasonic module 11 is located below the sea surface 107. In some embodiments, the ultrasonic module 11 is located close to the well 104.

The ultrasonic module 11 transmits signals to the returning drilling fluid 102 as the returning drilling fluid 102 passes through the channel 103, and the ultrasonic module 11 receives corresponding backscatter signals due to the particles (not shown) in the returning fluid 102 reflecting the signals.

In some embodiments, the ultrasonic module 11 is disposed outside the conduit 13 and transmits signals toward the conduit 13. In some embodiments, the ultrasonic module 11 is disposed on the conduit 13. For example, the ultrasonic module 11 is disposed on an outer surface of the conduit 13, or is disposed within or extends into the conduit 13. In this situation, the conduit 13 may further comprise a barrier (not shown) for isolating the ultrasonic module 11 from the returning drilling fluid 102, so as to provide a thermal insulation and reduce the pressure on the ultrasonic module 11.

In some embodiments, the ultrasonic module 11 comprises one or more ultrasonic sensors. FIG. 3 illustrates a schematic view of a plurality of ultrasonic sensors 111 spatially spaced from each other and disposed around the conduit 13.

In some embodiments, as is shown in FIG. 4, the conduit 13 comprises a riser 131 and a spool 132. The riser 131 and the spool 132 define the channel 103 for accommodating the drilling string 14 and the returning drilling fluid 102. The ultrasonic module 11 is disposed on the spool 132. The spool 132 isolates the ultrasonic module 11 and provides a working environment for the ultrasonic module 11, for example, it may provide a proper temperature and pressure environment for the ultrasonic module 11. In some embodiments, each end of the spool 132 is connected to a riser 131. In some embodiments, one end of the spool 132 is connected to a riser 131, and the other end of the spool 132 is connected to the LMRP (Lower Marine Riser Package, not shown) or a riser joint (not shown).

The ultrasonic module 11 transmits received backscatter signals to the process apparatus 12. Based on the backscatter signals, the process apparatus 12 obtains a flow characteristic of the returning drilling fluid 102, such as a velocity, at least a portion of flow profiles, a volumetric flow of the returning drilling fluid 102, or any combination thereof. In some embodiments, a proper algorithm, such as a Doppler spectrum analysis algorithm or a time-domain-based matrix pencil decomposition algorithm, may be used to obtain the flow characteristic based on the backscatter signals.

The process apparatus 12 detects a kick based on the flow characteristic of the returning drilling fluid 102 and drilling related data.

In some embodiments, the drilling related data include but are not limited to: backscatter signals obtained by transmitting signals to the drilling fluid 101 flowing to the well 104, operation data relating to a drilling operation, fluid characteristic data, or any combination thereof.

Backscatter signals of the drilling fluid 101 may be obtained by another ultrasonic module (not shown) transmitting signals to the drilling fluid 101. In some embodiments, the another ultrasonic module is located on the offshore device 106 or located above or close to the sea surface 107 (FIG. 1). In some embodiments, similar to the flow characteristic of the returning drilling fluid 102, the flow characteristic of the drilling fluid 101 may be obtained based on the backscatter signals of the drilling fluid 101.

In some embodiments, the operation data relating to the drilling operation include but are not limited to: a drilling mode for drilling the well 104, a pump stroke number, formation analysis data, a bit weight, pressure data comprising a stand pipe pressure and/or a borehole pressure, or any combination thereof; the drilling mode may include but is not limited to a trip in mode, a trip out mode, a flow check mode, a normal drilling mode, a mud circulation mode and so on. The drilling operation usually has an impact on the drilling fluid 101 and the returning fluid 102, so the operation data relating to the drilling operation may be helpful for the kick detection.

For example, if the drilling fluid 101 is pumped faster, i.e., the pump stroke number is bigger, the velocity of the drilling fluid 101 is faster and a rough flow rate of the drilling fluid 101 used in the kick detection may be estimated based on the pump stroke number. For another example, a change of bit weight, a change of pressure indicated by the pressure data, or a notable formation indicated by the formation analysis data may be helpful for the kick detection.

In some embodiments, the fluid characteristic data may indicate a density, a viscosity, or a component of the drilling fluid 101 or the returning drilling fluid 102. In some embodiments, the fluid characteristic data include but are not limited to: a mud weight, a surface mud cut, or a combination thereof. In some embodiments, an undesirable component in the returning drilling fluid 102, a change of density and so on indicated by the fluid characteristic data may be helpful for the kick detection.

In some embodiments, backscatter signals of the drilling fluid 101 and the pump stroke number may be regarded as a first portion of the drilling related data used to obtain a flow characteristic of the drilling fluid 101. In some embodiments, the operation data and the fluid characteristic data may be regarded as a second portion of the drilling related data used to detect the kick together with the flow characteristic of the returning drilling fluid 102.

In some embodiments, the process apparatus 12 detects the kick according to a change of difference between the flow characteristic of the returning drilling fluid 102 and the flow characteristic of the drilling fluid 101 obtained based on the first portion of the drilling related data.

For example, the process apparatus 12 identifies an ongoing or imminent kick when the change of difference between the flow characteristic of the drilling fluid 101 and the returning drilling fluid increases or increases faster than a threshold. In some embodiments, the process apparatus 12 identifies an ongoing or imminent kick when the velocity, at least a portion of flow profiles, or volumetric flow of the returning drilling fluid 102 increases faster (or faster than a threshold) than the velocity, at least a portion of flow profiles, or volumetric flow of the drilling fluid 101.

In some embodiments, the process apparatus 12 detects the kick based on the change of difference between the flow characteristic of the drilling fluid 101 and the returning drilling fluid 102 and the second portion of the drilling related data comprising the operation data relating to a drilling operation and/or fluid characteristic data. In some embodiments, when it is not easy to determine the kick only based on the change of difference, the second portion of the drilling related data may be helpful as the kick may be identified by some data in the second portion of the drilling related data.

In some embodiments, the process apparatus 12 detects the kick based on the flow change of the returning drilling fluid 102 when the drilling related data indicate any of a trip in mode, a trip out mode, a flow check mode, and a normal drilling mode. In these drilling modes, there is no drilling fluid 101 (such as in the trip in mode and the trip out mode), or the drilling fluid 101 is reducing (such as in the flow check mode), or the flow characteristic of the drilling fluid 101 is usually stable (such as in the normal drilling mode), so the process apparatus 12 detects the kick without the flow characteristic of the drilling fluid 101, for example, the process apparatus detects the kick when the velocity, at least a portion of flow profiles, volumetric flow of the returning drilling fluid 102 increases faster or faster than a threshold. In some embodiments, the process apparatus 12 detects the kick based on the flow change of the returning drilling fluid 102 and the second portion of the drilling related data when a trip in mode, a trip out mode, a flow check mode, or a normal drilling mode is indicated.

Referring to FIG. 1 and FIG. 2, in some embodiments, the process apparatus 12 comprises a first process module 121 located below the sea surface 107 and a second process module 122 located above the sea surface 107. In some embodiments, the first process module 121 obtains the flow characteristic based on the backscatter signals provided by the ultrasonic module 11 through the transmission module 108. In some embodiments, the second process module 122 detects the kick based on the flow characteristic of the returning drilling fluid 102 and the drilling related data. In some embodiments, the first process module 121 is located on the seabed 105. In some embodiments, the second process module 122 is located on the offshore device 106. In some embodiments, the kick detection system 100 comprises a communicating apparatus 17 for transmitting information between the first process module 121 and the second process module 122.

In some embodiments, when a kick is detected, the process apparatus 12 provides an instruction to a blowout preventer stack 16 of the well drilling system 10. In some embodiments, an operator input an instruction to the blowout preventer stack 16. The blowout preventer stack 16 operates to prevent the kick according to the instruction from the process apparatus 12 or from the operator.

In some embodiments, the kick detection system 100 comprises a warning apparatus 18 for providing a warning to an operator when the kick is detected. For example, the warning is provided through an alarm or a lamp with warning color such as yellow or red. In some embodiments, the warning apparatus 18 is located on the offshore device 106.

In some embodiments, the kick detection system 100 comprises a displaying apparatus 19 for displaying the flow characteristic, the drilling related data, a kick warning or any combination thereof. In some embodiments, the displaying apparatus 19 is located on the offshore device 106.

In some applications, the pressure of the fluids in the formation may be higher than the pressure of the drilling fluid 101. This may cause the fluids in the formation to enter into the channel 103 and join the returning drilling fluid 102, which results in a greater returning flow (or influx). This influx is a kick, and may result in a blowout and is harmful to well operators and the environment if uncontrolled. Therefore, a kick detection system is desired to detect the kick timely. The kick detection system 100 is simple enough to be employed for offshore usage and the kick detection is fast, so as to provide a warning timely to mitigate or avoid the harm of the kick.

FIG. 5 illustrates a schematic flow diagram of a kick detection method 20 for drilling a well in accordance with an embodiment of the present invention. The kick detection method 20 comprises a step 21 of transmitting signals to the returning drilling fluid 102 and receiving corresponding backscatter signals, a step 22 of obtaining a flow characteristic of the returning drilling fluid 102 based on the backscatter signals, and a step 23 of detecting a kick based on the flow characteristic of the returning drilling fluid 102 and the drilling related data.

In some embodiments, as is shown in FIG. 6, the step 23 comprises a step 231 of obtaining the flow characteristic of the drilling fluid 101 based on a first portion of drilling related data comprising a pump stroke number or backscatter signals of the drilling fluid 101, and a step 232 of detecting the kick based on a change of difference between the flow characteristic of the drilling fluid 101 and the flow characteristic of the returning drilling fluid 102.

In some embodiments, the step 232 comprises a step (not shown) of detecting the kick based on the change of difference between the flow characteristic of the drilling fluid 101 and the flow characteristic of the returning drilling fluid 102 and a second portion of the drilling related data comprising operation data relating to a drilling operation, fluid characteristic data, or a combination thereof.

In some embodiments, the step 23 comprises a step (not shown) of determining a flow change of the returning drilling fluid 102 based on the backscatter signals and detecting the kick based on the flow change, when the drilling related data indicate any of a trip in mode, a trip out mode, a flow check mode, and a normal drilling mode.

In some embodiments, the kick detection method 20 comprises a step (not shown) of operating a blowout preventer stack 16 to prevent the kick. In some embodiments, the kick detection method 20 comprises a step (not shown) of providing a warning to an operator when a kick is detected. In some embodiments, the kick detection method 20 comprises a step (not shown) of displaying the flow characteristic, the drilling related data, a kick warning or a combination thereof.

While the disclosure has been illustrated and described in typical embodiments, it is not intended to be limited to the details shown, since various modifications and substitutions can be made without departing in any way from the spirit of the present disclosure. As such, further modifications and equivalents of the disclosure herein disclosed may occur to persons skilled in the art using no more than routine experimentation, and all such modifications and equivalents are believed to be within the spirit and scope of the disclosure as defined by the following claims. 

What is claimed is:
 1. A kick detection system for drilling a well, comprising: an ultrasonic module for transmitting signals to a returning drilling fluid from the well, and receiving corresponding backscatter signals; and a process apparatus for obtaining a flow characteristic of the returning drilling fluid based on the backscatter signals, and detecting a kick based on the flow characteristic of the returning drilling fluid and drilling related data.
 2. The kick detection system of claim 1, wherein a first portion of the drilling related data comprises a pump stroke number or backscatter signals obtained by transmitting signals to a drilling fluid flowing to the well, the process apparatus obtains the flow characteristic of the drilling fluid flowing to the well based on the first portion of the drilling related data, and detects the kick based on a change of difference between the flow characteristic of the drilling fluid flowing to the well and the flow characteristic of the returning drilling fluid.
 3. The kick detection system of claim 2, wherein the process apparatus detects the kick based on the change of difference and a second portion of the drilling related data comprising operation data relating to a drilling operation, fluid characteristic data, or a combination thereof.
 4. The kick detection system of claim 1, wherein the process apparatus determines a flow change of the returning drilling fluid based on the backscatter signals and detects the kick based on the flow change, when the drilling related data indicate any of a trip in mode, a trip out mode, a flow check mode, and a normal drilling mode.
 5. The kick detection system of claim 1, wherein the process apparatus comprises a first process module below the sea surface and a second process module above the sea surface.
 6. The kick detection system of claim 5, comprising: a communicating apparatus for transmitting information between the first process module and the second process module.
 7. The kick detection system of claim 1, comprising: a warning apparatus for providing a warning to an operator when a kick is detected.
 8. The kick detection system of claim 1, comprising: a displaying apparatus for displaying the flow characteristic, the drilling related data, a kick warning or any combination thereof.
 9. A well drilling system, comprising: a drilling string for guiding a drilling bit and a drilling fluid to a well; a conduit defining a channel for accommodating the drilling string and a returning drilling fluid from the well; and a kick detection system comprising an ultrasonic module for transmitting signals to a returning drilling fluid from the well, and receiving corresponding backscatter signals; and a process apparatus for obtaining a flow characteristic of the returning drilling fluid based on the backscatter signals, and detecting a kick based on the flow characteristic of the returning drilling fluid and drilling related data.
 10. The well drilling system of claim 9, wherein the ultrasonic module comprises a plurality of ultrasonic sensors disposed on the conduit.
 11. The well drilling system of claim 9, wherein the conduit comprises a barrier for isolating the ultrasonic module from the returning drilling fluid.
 12. The well drilling system of claim 9, wherein the conduit comprises: a riser; and a spool connected to the riser for disposing and isolating the ultrasonic module and providing a working environment for the ultrasonic module.
 13. The well drilling system of claim 9, comprising: a blowout preventer stack for operating to prevent the kick according to an instruction from the process apparatus.
 14. A kick detection method for drilling a well, comprising: transmitting signals to a returning drilling fluid from the well, and receiving corresponding backscatter signals; obtaining a flow characteristic of the returning drilling fluid based on the backscatter signals; and detecting a kick based on the flow characteristic of the returning drilling fluid and drilling related data.
 15. The kick detection method of claim 14, wherein a first portion of the drilling related data comprises a pump stroke number or backscatter signals obtained by transmitting signals to the drilling fluid flowing to the well, and detecting the kick comprises: obtaining the flow characteristic of the drilling fluid flowing to the well based on the first portion of the drilling related data; and detecting the kick based on a change of difference between the flow characteristic of the drilling fluid flowing to the well and the flow characteristic of the returning drilling fluid.
 16. The kick detection method of claim 15, wherein detecting the kick comprises: detecting the kick based on the change of difference and a second portion of the drilling related data comprising operation data relating to a drilling operation, fluid characteristic data, or a combination thereof.
 17. The kick detection method of claim 14, wherein detecting the kick comprises: determining a flow change of the returning drilling fluid based on the backscatter signals and detecting the kick based on the flow change, when the drilling related data indicate any of a trip in mode, a trip out mode, a flow check mode, and a normal drilling mode.
 18. The kick detection method of claim 14, comprising: operating a blowout preventer stack to prevent the kick.
 19. The kick detection method of claim 14, comprising: providing a warning to an operator when a kick is detected.
 20. The kick detection method of claim 14, comprising: displaying the flow characteristic, the drilling related data, a kick warning or any combination thereof. 